Did you buy that one from Great Southern Coins?? JK I don't know my first impression was that it was dipped, but I'd like to hear other opinions.
I gotta admit, it looks cool. I wouldn't be surprised if it is natural. I found a 62 in an old roll that actually had a green shiney head.
Color was caused by the environment the coin was stored in. Looks like it might have been at the end of the roll tails out?